It's hard to know exactly how, or what, to say to someone with an eating disorder to make things all alright. Chances are you can't, but if you know someone who has fallen ill in this way you need to remember that what they're going through will always be much bigger and much tougher than your frustrations at not getting through to them.
From 2010 to 2013 I suffered quite badly with bulimia. I was always of average weight, so no body really looked at me any differently or noticed. It ended up getting quite bad, to the point where I was hospitalised at the end of 2011 with pneumonia and a collapsed lung - caused by the vomit that had been trapped in my chest area from purging all the time.
Many of us with eating disorders, like to personify the illness as a separate person or voice. 'Ana' for Anorexia and 'Mia' for Bulimia. Don't get me wrong; Ana is definitely not a 'friend' even though the internal voice I hear says otherwise. Personifying my eating disorder is definitely something that I found rather useful in my road to recovery.
By posting pictures of emaciated people to raise awareness, it is just reinforcing that stereotype so that the general public still have the idea that to be unwell the sufferer must be very thin and it makes sufferers feel that unless they look like that photo then they are not unwell enough to seek help.
A lot of my patients find eating in front of other people especially painful to do. Some need to know exactly what's in their food and drink and how many calories each piece of food has. But these are sensitive issues and the best you can do is to talk calmly and non-judgmentally to your friend or family member. It's not their fault, they are ill - many people think anorexia is a choice. It is not.